Optical lense grinding machines

ABSTRACT

A DEVICE, FOR USE WITH OPTICAL LENS EDGE GRINDING MACHINES HAVING A V-GROOVE GRINDING WHEEL, SUCH THAT THE LENS BEING GROUND MAY BE DEFLECTED TO CONTROLLED EXTENT AND THE APEX OF THE BEVEL FORMED ON THE LENS EDGE OFF-SET, AND MECHANISM FOR EFFECTING CONTROLLED DISPLACEMENT OF THE DEFLECTING ELEMENT WHICH MAY BE MOVED INTO AN INOPERATIVE POSITION WHEN NOT REQUIRED.

Feb- 16 1971 s. wRlGGLEswoRTH 3,562,963

OPTICAL LENSE GRINDING MACHINES Filed Nov. 6, 1968 5 Sheets-Sheet l.

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OPTICAL LENSE GRINDING MACHINES Filed Nov. e, 1968 s sheets-sheet z Ml nkl UM Sud..

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OPTICAL LENSE GRINDING MACHINES Filed Nov. 6, 1968 3 Sheets-Sheet s H555 F/e 5m NL; y WN/Lwam/ -Lwsmg 3,562,963 OPTICAL LENSE GRINDING MACHINES Stanley Wrigglesworth, The Firs, Spellowgate, Drifeld, Yorkshire, England Filed Nov. 6, 196s, ser. No. 773,863 Int. Cl. B24b 55/.00

U.S. Cl. 51-262 3 Claims ABSTRACT F THE DISCLOSURE A device, for use with optical lens edge grinding machines having a V-groove grinding wheel, such that the lens being ground may be deflected to controlled extent and the apex of the bevel formed on the lens edge off-set, and mechanism for effecting controlled displacement of the deflecting element which may be moved into an inoperative position when not required.

SPECIFICATION This invention relates to optical lens grinding machines used for forming a projecting bevel around the edge of spectacle lenses for securing them in the fronts of spectacles.

Normally such projecting bevel is symmetrical with equal width faces and is formed by a V-groove diamond or other suitable grinding 'wheel relative to which the lens is rotated with appropriate radial movement relative to the grinding wheel as a function of the machine according to the shape of the lens. Such normal bevel is suitable for the more usual thin lenses but not for thick lenses which have hitherto required the use of special grinding wheels, one for each particular off-set bevel or different face width which is expensive due to the high cost of grinding wheels and the time taken to mount the special grinding wheel in the machine when the edge of a thick lens has to be ground'.

Now therefore the object of the present invention is to provide an attachment for a lens grinding machine which may be brought into use to form an off-set bevel when a thick lens has to be ground and which does not affect the normal operation of the machine.

To this end according to the present invention an element, capable of deflecting a lens held by the normal lens holding means of an optical lens edge grinding machine relative to the V-groove grinding wheel of such machine, is mounted on an arm capable of moving such element between an adjustable operative position and an inoperative position clear of the periphery of said grinding wheel and the movement of said arm is controlled by means providing angular displacement of the arm about an axis along it is also axially movable by said means.

The element comprises a flat metal piece extending in operative position at an angle matching that of the working face of the V-groove grinding wheel which, in that position, it at least partially overlaps; and extends at such angle to a body portion which is, preferably detachably, mounted at or near the free end of its mounting arm. In operative position the element limits the penetration of the lens into the V-groove of the grinding wheel or deflects it so that its edge is more worked on by the other face of the groove than that partly covered by the element so that the apex of the formed bevel is off-set to a desired extent.

In inoperative position the element is displaced to one side of the grinding wheel to lbelow the periphery thereof and in movement between such positions the mounting arm is rocked to raise the element above the periphery of the grinding wheel, then linearly displaced to bring the element within the groove in the grinding wheel and finally United States Patent O ICC reverse rocked to bring the element into operative position and at a desired setting, and vice versa.

The angular and linear movement is conveniently effected by a linear displacement of a spindle which carries at its end the mounting arm and which has a radially projecting cam follower located in a substantially kidneyshaped cam slot for imparting the required angular movement thereto.

The linear displacement of said spindle is preferably effected by rotation of a threaded member which is moved axially as a function of its rotation, when such member may be fast with an outer sleeve an end edge of which may traverse a scale on a fixed part through which the spindle extends and so indicate the degree of setting of the element in its operative position. It is further preferred that the end of the spindle abuts the end of the rotatable axially displaceable member for displacement thereby and that such spindle is spring loaded to maintain such abutting engagement.

The cam slot is conveniently provided in the fixed part through which the spindle extends, when such slot is covered by the outer sleeve and such fixed part may be formed with an end peripheral flange by means of which the appliance may be fixed to the wall of the housing in which the grinding wheel of the machine is located, with the element and its mounting arm within the housing, so that it may be built into new grinding machines as well as affixed to existing grinding machines.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a plan view of the attachment shown in position on the casing of a lens grinding machine surrounding the conventional V-groove grinding wheel and an adjacent flat face grinding wheel and containing the customary water jets, the lens deflecting element being shown in retracted inoperative position with its operative position indicated in chain line,

FIG. 2 is a front elevation of the illustration in FIG. 1 with part of the front wall of the casing broken away so that the deflecting element and grinding wheel peripheries may be seen,

FIG. 3 is a section taken on the line III- III of FIG. l, the deflecting element being shown in operative position with its inoperative position shown in dotted line and an intermediate position in travelling from the one position to the other shown in chain line,

FIG. 4 is a vertical section through the operating p0rtion of the attachment in a view similar to FIG. 2,

FIG. 5 is an elevation of the operating portion of the attachment from the opposite side to that shown in FIG. 4 and with part of the outer sleeve broken away to show the cam slot, and

FIGS. 6A, 6B and 6C are detail views showing the deflecting element fully masking one face of the V-groove grinding wheel, partly masking the one face of the grinding wheel, i.e., in its operative position, and in its inoperative position respectively and shown relative to the setting of the operating portion of the attachment.

DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION The lens deflector attachment forming the present invention is for use with conventional lens edge grinding machines, having a V-groove grinding wheel and usually also an adjacent flat surface grinding wheel, which being well known do not need to be described herein nor illustrated in the accompanying drawing beyond Showing of the V-groove grinding wheel 1 and its adjacent flat face grinding wheel 2, the peripheries of which extend through a guard plate 3 in a casing comprising the walls 4, 5, 6 and 7 and containing the usual water jet nozzles 8 and 9.

The invention consists in the provision of the ilat element 10, conveniently with a contour edge substantially as shown, disposed parallel to one face of the V-groove of the grinding wheel 1 and in operative position partially overlaps such face, to an adjustable extent, to limit the penetration of the lens (the edge of which is to be ground to provide a projecting bevel) into the V-groove of the grinding wheel 1 or deflect it so that its edge is more worked on by the unmasked face of the V-groove such that the apex of the formed bevel is off-set to a desired extent and as required particularly for a thick lens.

The element is carried, preferably detachably, at one end of a mounting arm 11 secured on the end of a spindle 12 in an arrangement in which the extent of masking of the one working face of the V-groove of the grinding Wheel 1 may be adjusted by small angular movement of the arm 11 by rotation of the spindle 12 and in which the element 10 may be moved away from the V-groove by rocking of the arm 11, then moved laterally to one side of the grinding wheel 1 on axial displacement of the spindle 12, and finally moved into inoperative position clear of the periphery of the grinding wheel 1 on reverse rotation of the spindle 12.

The rotational and axial displacement of the spindle 12 is conveniently effected from outside the casing and a mechanism for effecting such controlled movement is hereinafter described with particular reference to FIGS. 4 and 5 of the drawings.

The spindle 12 extends through a bearing member 13 in a tube 14 having an end peripheral flange 15 by means of which the device may be attached to the casing wall 4. Internally the end of the spindle 12 is fast with a member 16 slidable in the bore of the tube 14 and carrying a projecting cam follower 17 working in a substantially kidney-shape cam slot 18 provided in the wall of the tube. The spindle 12 is acted upon by a spring 19 extending between the member 16 and bearing member 13 to urge the member 16 into contact with the end of a threaded rod 20 extending through a nut 21 fast in the end of the tube 14 so that rotation of such rod 20` causes it to move axially and so axially displace the spindle 12. The axial displacement of the spindle 12 by the threaded rod 20 also causes rotation of the former due to the cam follower 17 moving along the cam slot 18, and there is therefore controlled axial and rotational displacement of the spindle 12 to bring the element 10 to desired position for required lens edge grinding or into inoperative position when the grinding wheel is to perform its normal operations. A knurled or otherwise roughened knob 22 on the exposed end of the rod 20 facilitates the digital rotation thereof.

The rod 20 is also fast with a thimble or outer sleeve 23 which extends over the tube 14 and covers the cam slot 18 therein. The end edge 23' of the sleeve 23 provides a datum of the extent of axial displacement of the spindle 12 and hence of the element 10 relative to a scale 24 provided on the outer surface of the tube 14, and such end of the sleeve 23 may be bevelled and provided with a scale 2S readable against a mark or line on the tube 14 to indicate the extent of rotation of the spindle 12.

Thus as shown in FIG. 6A on maximum axial displacement of the spindle 12, zero position on the scale 24, and maximum rotation of the arm 11 so that the element 10 fully masks the one face of the V-groove of the grinding wheel 1, zero position on the scale 25, the element 10 is in null position and no lens edge grind can take place. In FIG. 6B in the operative position of the element 10 it only partly masks the one face of the V-groove to an extent which can be read from the scales 24 and 25. In FIG. 6C when the element 10 is in inoperative position this is shown by the other end zero of the scale 24. The device is therefore convenient to use by being brought into operation when required and easily adjusted to form lens bevel edges with desired off-set.

I claim:

1. An edge grinding machine for forming a bevel on the edge of an optical lens comprising,

a V-groove grinding wheel,

an element for deilecting the lens being ground so that the apex of the bevel is offset,

said element being ilat and normally parallel to one face of said V-groove which in operative position it partly overlaps,

means for mounting said element at the end of an arm,

a spindle on an end of which said arm is mounted,

means for adjusting the position of said element relative to one face of the V-groove of said grinding wheel,

means for effecting controlled rotational and axial displacement of said spindle,

and means for moving said element to an inoperative position.

2. The device as claimed in claim 1 wherein the means for effecting controlled displacement of said spindle comprises a tube having a bearing member at one end through which said spindle extends, a member fast on the end of said spindle for sliding movement in the bore of said tube, a cam slot in the wall of said tube, a cam follower projecting from said member and working in said cam slot, a threaded rod extending through a nut fast at the other end of said tube, a spring between said member and said bearing member for urging said spindle for its end to abut the end of the threaded rod, and a knob on the other end of said threaded rod to facilitate digital rotation thereof.

3. The appliance claimed in claim 2 including a sleeve fast with said threaded rod and extending over said tube, the end of said sleeve providing a datum relative to a scale provided on said tube.

References Cited UNITED STATES PATENTS 250,691 1881 Valiquit 51-101.1 1,269,680 1918 Bugbee 51-101.1 2,293,291 8/ 1942 Gaspari 51-106 2,329,713 9/1943 Goddu .S1-101.1 3,315,415 4/1967 Lannom 51-10l.1

WILLIAM R. ARMSTRONG, Primary Examiner U.S. Cl. X.R. 51-101 

